Flexible couplings, dampers, gearwheels and like devices



Feb. 17, 1959 I L. P. CROSET 2,873,590

FLEXIBLE COUPLINGS, DAMPERS, GEARWHEELS AND LIKE DEVICES Filed Dec. 5,1956 2 Sheets-Sheet '1 wvewrok ATTORNEY Feb. 17, 1959 L. P. CROSET2,873,590

, FLEXIBLE COUPLINGS, DAMPERS, GEARWI'JEELS AND LIKE DEVICES Filed Dec.5, 1956 2 Shets-Sheet 2 Fig .4.

4 44 37 1 38 7 I'TTI I N LBJ LU 46 E i II //VVEN7'OR Z 00/; PA 04Cfiasfr BY V/WL XXMJ United States Patent "ice FLEXIBLEv COUPLINGS,DAMPERS, GEARWHEELS AND LIKE DEV ICES Claims. priority, a plicationGreat Britain Decem er 16,1955

3 Claims. cr st-14 This invention relates to flexible couplings,dampers, gearwheels, and like devices comprising two co-axial members,two sets of blades which extend radially and axially of said members andwhich blades are connected alternately in the circumferential directionto one and the other of said co-axial members, and an outer drumsurrounding the blades so as to form cells which contain blocks ofrubber or synthetic rubber-like material so that each block engagesadjacent blades carried by the said members respectively.

The main object of the present invention is to enable the blocks todeform with a rolling action engaging with the cell walls anddisengaging therefrom, and to provide a greater degree of deformation ofthe blocks and there fore a lower coupling stiffness for a given cellvolume. A further object is to facilitate varying of the torsionaldeflection or coupling stiffness.

According to the invention the block in axial view and the roots of theblades are of correspondingly shaped curvature at two opposite parts ofthe block, one having an arc of contact of more than 90, the other ofless than 90 around the block, leaving two oppositely disposed parts,extending Over similar angles, out of contact with the cell but movableinto engagement with the cell under increasing load by an approximatelyrolling engagement.

Preferably the blocks are of circular cross-section and have a radius inthe free condition equal to or slightly greater than that of the root ofthe blade and approximately half the radial height of the cell.

The invention will now be further described with reference to theaccompanying diagrammatic drawings wherein:

Figure 1 is a sectional view of part of a flexible coupling made inaccordance with the invention;

Figure 2 is a similar sectional View showing somewhat larger blocks; and

Figures 3 and 4 are sectional views on the lines 3-3 and 44 on Figure 1.

In the drawings a cylindrical roller is shown the free diameter of whichis about equal to the radial dimension of the cell formed by a blade 11on an inner member 12 and the adjacent blade 30' on the outer member 15.The outer member blade has a circular portion 17 to 18 and the innermember blade has a circular portion 20 to 21 which have a radius equalto half the radial height of the cell, the radius of the roller 10, inthe free condition, being equal to or greater than that of the bladeroot. Each blade then continues as a free end having walls parallel toeach other and it will be seen that the radius ed portion of an outermember blade is slightly greater than an angle of 90 and that of theinner member blade slightly smaller than an angle of 90. Thisarrangement leaves two spaces 24, 25 in each cell oflset at 180 fromeach other into which the rollers can be forced when under load. Therubber roller as it deforms has an approximately rolling contact withthe parallel walls of the blades and the adjacent wall of the outer2,873,590 Patented Feb. 17, 1959 member. It unrolls, from these surfacesas the load is reduced. The rollers may completely fill the axialdimensions of the cell. The length of the curves 20 to 21 of the bladeson the inner member are about equal to the length of the parallel parts(such as 20 to 26) e. g. to of such parts. The length of the curves 17to 18 of the blades on the outer member 15 are greater than the parallelparts, of said blades, e. g. 110 to of the length of such parts.

The left-hand side of Figure 1 shows a roller which in the freecondition has a diameter equal to the radial height of the cavity, thatis a radius equal to that of the blades, which in the noload orassembled condition have a pitch of 30, secondly, this figure shows,between blades 11 and 30, a roller subjected to maximum de formationwhich corresponds to a torsional deflection of 4, this in one sense ofrotation being a leading or driving roller or cavity, the pitch betweenthe blades being 304=26 and the trailing cavity formed by blades 30 and11 showing the roller half way between the adjacent blades which are ata pitch of 30 +4=34, the roller making tangential contact only with theperipheries of the inner and outer members.

Figure 2 shows, on the right-hand side, a roller 10 which in the freecondition has a radius slightly greater than that of the root of theblade or half the radial height of the cavity and, therefore, uponinsertion undergoes deformation, the pitch of the blades in the unloadedcondition being also 30. The driving roller 33 is shown under maximumdeformation, the angle between the blades 11 and 30 being 302=28.Trailing rollers 10 are shown under a slightly compressed condition, theangle between blades 11 30 and 11, 30 being 30+2=32.

It will be seen that whether it is inserted withor withoutpre-compression, depending upon its diameter being equal to or slightlylarger than the radial height of the cavity or cell, the roller makesfull contact with the large fillet at the root of the blades and spacesare left for deformation under torque load only at 24 and 25 and/ or 38and 32 (see Figure 3), space 24 (see Figure 2) between the periphery ofthe outer members and the parallel portion or tip of the blade of theinner member being larger than the space 25, there being no rubbingaction at any point during deformation but only rolling action betweenroller and cavity surfaces. The degree of torsional deflection andcoupling stiffness can be varied by the simple expedient of varying theroller diameter for a given number of pairs of rollers, roller hardnessand pitch circle diameter of the rollers.

In Figures 3 and 4, a driving flange 44 is shown to which the outermember 15 is bolted. A cover 45 is bolted to the other side of member15'. The parts 44, 45 close the ends of the cells. The trailing blocksnormally have a clearance 38, 39, from the parts 44, 45, and in somecases also a clearance 40, 41 from the blades 11, 30, 11 but makecontact under load as at 36, 37 and 46, 47.

The coupling of the present invention has a greater torque capacity dueto the blades being able to withstand greater bending loads.

As there is no rubbing action but rolling action only between the rollerand cavity surfaces it is possible to use unmachined cavities for manyapplications.

Due to the considerable reduction in blade bending stress, forged orcast steel components need not be used exclusively but material of lowerductility, such as high grade cast iron, may be used with advantage.

I claim:

1. A flexible vibration damping apparatus comprising two approximatelyco-axial members, two sets of blades which extend radially and axiallyof said members and which blades are connected alternately in thecircumferential direction to one and the other of said co-axial members,an outer drum surrounding the blades so as to form cells, blocks ofelastic material in said cells, each block and the roots of the bladesbeing of correspondingly shaped curvature at two opposite parts of theblock, one of said parts of the block having an arc of contact of morethan 90, the other of less than 90 around the block, leaving twooppositely disposed parts, extending over similar or smaller angles, outof contact with the cell but movable into engagement with the cell underincreasing load by an approximately rolling engagement, said blades eachhaving parallel sides at it's free end whereby spaces are provided whenthe blocks are unloaded which spaces are substantially filled by theblocks when these are deformed under load.

2. Apparatus as claimed in claim 1 wherein the blocks are of circularcross-section and have a radius in the free condition equal to orslightly greater than that of the root of the blade and approximatelyhalf the radial height of the cell.

3. Apparatus as claimed. in claim 1 wherein the length of the curvatureof the roots of the blades on the inner member is '80 to 120% of theparallel parts of said blades and the length of the curvature of theroots of the blades on the outer member being greater than the parallelparts of these blades.

References Cited in the file of this patent UNITED STATES PATENTS

